Orthopedic stabilization devices and methods for installation thereof

ABSTRACT

Embodiments herein are generally directed to fastener or fixation members, such as bone screws, for use in orthopedic stabilization assemblies.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation of U.S. patent applicationSer. No. 14/491,125, filed Sep. 19, 2014, which is herein incorporatedby reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to orthopedic stabilization devices andmethods used to install these devices.

BACKGROUND OF THE INVENTION

Many types of spinal irregularities can cause pain, limit range ofmotion, or injure the nervous system within the spinal column. Theseirregularities can result from, without limitation, trauma, tumor, discdegeneration, and disease. Often, these irregularities are treated byimmobilizing a portion of the spine. This treatment typically involvesaffixing a plurality of fixation devices to one or more vertebrae andconnecting the devices to an elongate rod that generally extends alongthe length of the spine.

Treatment for these spinal irregularities often involves using a systemof fixation devices to attain stability between spinal segments.Instability in the spine can create stress and strain on neurologicalelements, such as the spinal cord and nerve roots. In order to correctthis, various implants can be used to restore the correct alignment andposition of the vertebral bodies. In some cases, a stabilization device,optionally in conjunction with a vertical solid member, can help restoreand/or correct the alignment of spinal segments, thereby reducing painor preventing further injury to the spine.

Stabilization devices may include a bone fastener, such as a screw, forfastening the device to vertebra. Some stabilization devices further mayinclude a coupling element (e.g., a tulip element) for coupling the bonefastener to the vertical solid member (e.g., elongate rod). Clamp and/orwedge elements may be used to secure the bone fastener in the couplingelement. A locking cap may also be used to secure the rod in thecoupling element.

SUMMARY OF THE INVENTION

Some embodiments herein are directed to a spinal stabilization anchorthat can include a compressible head; a distal collar separated from thehead by a channel; and an elongate, longitudinally-curved shankextending therefrom and comprising at least one friction member.

Other embodiments herein are directed to a spinal stabilization systemthat can include a spinal stabilization anchor comprising a compressiblehead, a distal collar separated from the head by a channel, and anelongate, longitudinally-curved shank extending therefrom, wherein theshank further comprises at least one friction member; and a fastenermember comprising a threaded shaft having a distal tip configured to bepivotably coupled to the spinal stabilization anchor.

Some embodiments herein are directed to a method of installing a spinalstabilization assembly that can include inserting a spinal stabilizationanchor into a bone, wherein the spinal stabilization anchor includes acompressible head, a distal collar separated from the head by a channel,and an elongate, longitudinally-curved shank extending therefrom,wherein the shank further comprises at least one friction member;inserting a fastener member into the bone, wherein the fastener membercomprises a threaded shaft having a distal tip configured to bepivotably coupled to the spinal stabilization anchor; and coupling thefastener member to the spinal stabilization anchor by inserting thecompressible head into the distal tip.

Other embodiments herein are directed to a spinal stabilization systemthat can include a fastener member comprising a threaded shank and ahead; an elevation member configured to be disposed on the fastenermember and configured to adjust a length of the spinal stabilizationsystem; a coupling member configured to couple the fastener member to arod and comprising a rod-receiving channel and a proximal end withinterior threading; and a set screw configured to mate with the proximalend of the coupling member.

Some embodiments herein are directed to a fastener member comprising athreaded shank and a threaded head, the threaded head further comprisinga socket; an elevation member comprising a body having a proximal face,a distal face, a threaded hole extending therethrough and configured tomate with the threaded head, and a first connector member; a couplingmember comprising: an upper portion having two arms defining arod-receiving channel, and a lower portion having a stem and at a secondconnector member, wherein the stem is configured to be wedged in thesocket of the fastener member and the second connector member isconfigured to mate with the first connector member; and a locking memberconfigured to engage the upper portion of the coupling member.

Other embodiments herein are directed to a spinal stabilization systemthat can include a fastener member comprising a threaded shank extendinglongitudinally from a threaded head, the threaded head furthercomprising a socket; a gear member comprising an outer surface with aplurality of teeth, a threaded hole configured to mate with the threadedhead, and a proximal surface having a receptacle thereon; a couplingmember comprising: an upper portion configured to receive a rod; and alower portion having a stem configured to be keyed in the socket of thefastener member and a slotted collar having a lip configured to bereceived in the receptacle; and a locking member configured to engagethe upper portion of the coupling member.

Some embodiments herein are directed to a method of installing a spinalstabilization system that can include providing a spinal stabilizationsystem comprising: a fastener member comprising a threaded shankextending longitudinally from a threaded head, the threaded head furthercomprising a socket; a gear member comprising an outer surface with aplurality of teeth, a through bore with internal threading mated withthe threaded head, and a proximal surface having a receptacle thereon; acoupling member comprising: an upper portion configured to receive arod, and a lower portion having a stem keyed in the socket of thefastener member and a slotted collar having a lip received in thechannel surrounding the through bore; and a locking member configured toengage the upper portion of the coupling member; engaging the lockingmember with the proximal end of the coupling member to secure a rod inthe rod-receiving channel; and adjusting a position of the couplingmember along a longitudinal axis of the system after the rod is securedin the rod-receiving channel.

Other embodiments herein are directed to a spinal stabilization systemthat can include a fastener assembly, comprising: a fastener membercomprising a threaded shank extending longitudinally from a threadedhead, the threaded head further comprising a socket; and a compressionmember comprising a rounded head, an elongate body, and a longitudinalbore extending therethrough, wherein a portion of the longitudinal borein the rounded head comprises a socket, and a portion of thelongitudinal bore in the elongate body is configured to engage the headof the fastener member, and a clamp assembly, comprising: a clamp membercomprising a rounded inner surface configured to receive the roundedhead of the compression member, a rounded outer surface, and an openingconfigured to receive the elongate body of the compression membertherethrough; a coupling member comprising: a rod-receiving portioncomprising a channel, a fastener-receiving portion comprising anaperture having a rounded interior surface configured to receive theclamp member, and a locking portion comprising a first lockingreceptacle; and a first locking member configured to be received withinthe first locking receptacle of the coupling member.

Some embodiments herein are directed to a spinal stabilization systemthat can include a pedicle screw assembly, comprising: a fastener membercomprising a threaded shank extending longitudinally from a threadedpost, the threaded post further comprising a socket; and a compressionnut comprising a rounded head, an elongate body, and a longitudinal boreextending therethrough, wherein a portion of the longitudinal bore inthe rounded head comprises a socket configured to receive a driver, anda portion of the longitudinal bore in the elongate body comprisesthreading configured to mate with the threaded post of the fastenermember; and a polyaxial clamp assembly, comprising: a clamp membercomprising a rounded inner surface configured to receive the roundedhead of the compression nut, a rounded outer surface, and an openingconfigured to receive the elongate body of the compression nuttherethrough; a rod-locking member; a fastener-locking member; and acoupling member comprising: a rod-receiving channel, a first receptacleconfigured to receive the rod-locking member, a through bore having arounded interior surface and configured to receive the clamp member, anda second receptacle configured to receive the fastener-locking member.

Other embodiments herein are directed to a method of installing a spinalstabilization system that can include providing an assembled spinalstabilization system that can include a coupling member comprising: arod-receiving portion comprising a channel, a fastener-receiving portioncomprising an aperture having a rounded interior surface, and a lockingportion comprising a first locking receptacle; a clamp member disposedin the aperture of the fastener-receiving portion, the clamp membercomprising a rounded inner surface, a rounded outer surface, a chamber,and an opening configured to receive the elongate body of thecompression member therethrough; a first locking member disposed in thefirst locking receptacle of the coupling member; a compression membercomprising a rounded head disposed in the chamber, and furthercomprising an elongate body and a longitudinal bore extendingtherethrough, wherein a portion of the longitudinal bore in the roundedhead comprises a socket, and a portion of the longitudinal bore in theelongate body is configured to engage the head of the fastener member;and a fastener member threaded into the longitudinal bore of thecompression member and comprising a threaded head and a threaded shankextending longitudinally from the threaded head. These embodiments canalso include driving the fastener member into a bone; inserting a rodinto the channel; adjusting a position of the clamp assembly along alongitudinal axis, after the rod is inserted into the channel; threadingthe first locking member into the first locking receptacle and over thesecuring member to secure the fastener assembly at an angle relative tothe clamp assembly; and threading the second locking member into thesecond locking receptacle to secure the rod in the channel.

Some embodiments herein are directed to a spinal stabilization systemthat can include a screw comprising a post, a threaded shank extendingdistally from the post, and a socket; a torsion shaft comprising: adistal section configured to be received within the socket; a bodycomprising at least one cut; and a proximal section comprising anexternally-threaded portion and a tool-receiving recess; a relief screwcomprising a body having an externally-threaded portion, a proximal endhaving a tool-receiving recess, and a bore extending longitudinallytherethrough, wherein the bore comprises an internally-threaded sectionconfigured to mate with the externally-threaded section of the torsionshaft; and a compression nut comprising a proximal end having atool-receiving recess, a body, and a bore extending longitudinallytherethrough, wherein the bore comprises an internally-threaded portionconfigured to mate with the externally-threaded body of the reliefscrew.

Other embodiments herein are directed to a spinal stabilization systemthat can include a fastener member comprising a head, a threaded bodyextending longitudinally from the head, and a socket; a torsion membercomprising: a distal section configured to be received within thesocket, a flexible body, and a proximal section comprising anexternally-threaded portion and a tool-receiving recess; a relief membercomprising a bore extending longitudinally therethrough, a bodycomprising external threading, and a proximal end having atool-receiving recess, wherein the bore comprises an internally-threadedportion configured to mate with the externally-threaded portion of thetorsion member, and a compression member comprising a proximal endhaving a tool-receiving recess and a bore extending longitudinallytherethrough, wherein the bore comprises an internally-threaded portionconfigured to mate with the external threading of the relief member.

Some embodiments herein are directed to a spinal stabilization systemthat can include a fastener member comprising a head, a threaded bodyextending longitudinally from the head, and a socket; a torsion membercomprising a distal section, a flexible body, and a proximal sectioncomprising an externally-threaded segment and a tool-receiving recess,wherein at least the distal section is disposed within the socket of thefastener member; a relief member comprising a body comprising externalthreading and a bore extending longitudinally therethrough, wherein thebore comprises a proximal end having a tool-receiving recess and aninternally-threaded portion engaged with the externally-threaded portionof the torsion member, and a compression member comprising an boreextending longitudinally therethrough and a proximal end having atool-receiving recess, wherein the bore comprises a threaded portionengaged with the external threading of the relief member.

Other embodiments herein are directed to a method of installing a spinalstabilization system that can include providing an assembled spinalstabilization system; creating a passageway through a proximal bone anda distal bone, wherein the passageway has a diameter that is smaller inthe distal bone than in the proximal bone; driving the threaded body ofthe fastener member through the passageway into the distal bone; anddriving the compression member through the passageway into the proximalbone to alter the relative alignment between the bones.

Further areas of applicability of the present invention will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating certain embodiments of the invention, are intended forpurposes of illustration only and are not intended to limit the scope ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIGS. 1A-B illustrate perspective views of one embodiment of a spinalstabilization anchor as disclosed herein:

FIG. 2A illustrates a perspective view of one embodiment of a fastenermember as disclosed herein;

FIG. 2B is a partial cross-section view of a distal end of the fastenermember illustrated in FIG. 2A;

FIG. 2C is a partial cross-section view of a spinal stabilization anchorcoupled to a fastener member;

FIGS. 3A-E are perspective views, in partial cross-section, of onemethod of installing a spinal stabilization system as disclosed herein:

FIG. 4A illustrates a perspective view of one embodiment of a fastenermember as disclosed herein:

FIG. 4B illustrates a perspective view of an elevation member coupled toa fastener member;

FIGS. 4C-D illustrate perspective views of a coupling member, elevationmember, and fastener member;

FIGS. 5A-C illustrate partial cross-section views of an assembledcoupling member, elevation member, and fastener member;

FIGS. 6A-F illustrate perspective views of one method of installing aspinal stabilization anchor as disclosed herein;

FIGS. 7A-B illustrate perspective views of one embodiment of a spinalstabilization system as disclosed herein;

FIG. 8 illustrates an exploded view of a fastener assembly;

FIGS. 9A-B illustrate a perspective view and an exploded view of a clampassembly;

FIGS. 10A-B illustrate the engagement of a spinal stabilization systemwith a driver;

FIGS. 11A-C illustrate installed spinal stabilization systems;

FIG. 12 illustrates the translation of a compression member as describedherein;

FIG. 13 illustrates a fastener member and torsion member of a spinalstabilization system described herein;

FIG. 14 illustrates a relief member and compression member of a spinalstabilization system described herein;

FIGS. 15A-B illustrate a cross-sectional view and a perspective view ofan assembled spinal stabilization system;

FIGS. 16A-D illustrate a method of installing a spinal stabilizationsystem described herein; and

FIG. 17 illustrates multiple spinal stabilization systems installed in aspine.

DETAILED DESCRIPTION

Spinal stabilization devices, such as screw-based systems, may be usedto correct or restore vertebral alignment. Using these types of systems,one or more screws may be implanted in the affected vertebrae. In someinstances, the screw may loosen and/or back out of the vertebrae overtime and the screw placement may need to be revised, e.g., in asubsequent surgical procedure. This may happen, for example, if thescrew was placed in osteoporotic bone. One method for revising the screwplacement can include removing the old screw and implanting a largerscrew, which may be effective at gripping the bone, but which may alsoreduce the overall structural stability of the bone. Furthermore, asubsequent surgical procedure can present other additional risks to apatient. Accordingly, disclosed herein are new and improved spinalstabilization devices that can increase stability of the interfacebetween a bone and a screw in the cancellous region of a vertebral body,reduce the tendency of a screw to loosen and/or back out, and/or reducethe diameter of a screw used in a revision procedure.

Some screw-based systems include a plurality of screws inserted into thepedicles of adjacent vertebrae and coupled to an elongate rod. In someprocedures (e.g., to correct a spinal deformity), screws and rods may beimplanted that extend along a significant length of a spine. In thesetypes of procedures, as well as others utilizing a smaller number ofscrews and/or rods, it can be difficult to align all of the screws at aproper depth to securely couple with the rod(s). Accordingly, disclosedherein are new and improved spinal stabilization devices that allow thedepth of a screw to be adjusted after it is coupled to a rod, and/orwithout needing to drive the screw further into or out of a vertebra.

Various devices, such as pedicle screw systems and/or intervertebralcages, may be used to treat spondylolisthesis, a condition in which oneor more vertebrae are displaced in the anterior direction.Advantageously, disclosed herein are new and improved spinalstabilization devices that can correct vertebral displacement using asingle screw, and optionally, in a minimally-invasive procedure.Components of all of the spinal stabilization devices disclosed hereincan be made of materials known to those skilled in the art, includingmetals (e.g., titanium), metal alloys, polymers (e.g., PEEK), allograft,and/or combinations thereof. The components can also be machined and/ormanufactured using techniques known to those skilled in the art.

Turning now to FIGS. 1A-B, a perspective view of a spinal stabilizationanchor 2 is illustrated in accordance with embodiments described herein.As illustrated, the spinal stabilization anchor 2 may include a head 4,a collar 6, a shank 8, and a channel 10. In some embodiments, the spinalstabilization anchor 2 may be referred to as a spike or nail. The head 4can be rounded. In some embodiments, at least a portion of the head 4may be compressible (e.g., the diameter of a rounded head 4 may bereversibly reduced upon application of force). The head 4 may becompressible as the result of various materials and/or features. Forexample, in some embodiments the head 4 can include at least one slot12. As illustrated in FIGS. 1A-B, the head 4 can include four slots. Thehead 4 can further include a tool-receiving socket 14. Thetool-receiving socket 14 can be configured to receive a driver or otherinsertion tool.

As illustrated in FIGS. 1A-B, the collar 6 can include one or morealignment members, such as protrusions 16. The protrusions 16 canadvantageously be used to align or guide the spinal stabilization anchor2 during the installation process. In other embodiments, the collar 6may include grooves, slots, or other features to assist withinstallation. As illustrated in FIGS. 1A-B, the collar 6 may bepositioned distal to the head 4, and may be separated from the head 4 bychannel 10. The channel 10 can surround the head 4.

As illustrated in FIGS. 1A-B, the shank 8 extends distally from thecollar 6 and can have an elongated shape, terminating in a distal tip20. The distal tip 20 can take on any shape, such as sharp, pointed, orblunt. The shank 8 may be curved along a longitudinal axis. Accordingly,as illustrated in FIGS. 1A-B, the pointed distal tip can be laterallydisplaced relative to the head 4. In other embodiments, the distal tip20 may be laterally displaced relative to the head 4 by angling awayfrom the head 4, instead of curving away from the head 4.

The shank 8 can also include at least one friction member 18 disposedthereon. As illustrated in FIGS. 1A-B, the shank 8 may include aplurality of friction members, such as teeth, bumps, or ratcheting. Insome embodiments, the shank 8 may include one, two, or more rows offriction members. For example, as illustrated in FIGS. 1A-B, the shank 8can include two rows of teeth. One or more friction members 18 may beangled towards the proximal end of the spinal stabilization anchor 2, soas to advantageously prevent or reduce the backing out of the anchor 2from a bone.

Some embodiments herein are directed to a spinal stabilization system100. The spinal stabilization system 100 can include the spinalstabilization anchor 2 and a fastener member 22, illustrated in FIGS.2A-C. In some embodiments, the fastener member 22 may be a bone screw,such as a pedicle screw and/or a compression screw. For example, thefastener member 22 may be any of the bone screws described herein.Additionally, although illustrated with a rod-coupling member 35 in FIG.2A, those skilled in the art may appreciate that the rod-coupling member35 is an optional component of the assembly.

The fastener member 22 can include a threaded shaft 24 and a distal tip26. The distal tip 26 can be configured to be pivotably coupled to thespinal stabilization anchor 2. As illustrated in FIGS. 2B-C, the distaltip 26 can include a recess 28 that is configured to receive the head 4.In embodiments where the head 4 is rounded, the recess 28 may also havea rounded interior surface which corresponds to the shape of the head 4.The distal tip 26 can also include a lip 30 that is configured to bereceived in the channel 10 of the spinal stabilization anchor 2. Asillustrated in FIG. 2C, the collar 6 may function as a ledge upon whichat least a portion of the distal-most surface 32 of the distal tip 26may rest.

Embodiments herein are also directed to methods of installing the spinalstabilization system 100 described herein. Those skilled in the art mayappreciate that the spinal stabilization anchor 2 and fastener member 22may be installed in a variety of different bones, including the variousvertebrae as well as other non-vertebral bones. Additionally, the spinalstabilization anchor 2 may be inserted into a bone using any means knownto those skilled in the art.

In one example, prior to installing the spinal stabilization anchor 2,the installation site may be prepared by creating (e.g., drilling) ahole 37 through which the spinal stabilization anchor 2 may pass. Asillustrated in FIG. 3A, the hole 37 may be formed in a posterior sectionof a vertebra; however, the exact position can vary depending on theparticular procedure being performed.

Once the hole 37 is formed, the spinal stabilization anchor 2 may beinserted through the hole 37 and into the bone, as illustrated in FIGS.3A-B. The spinal stabilization anchor 2 may be inserted into any portionof the bone as appropriate for the particular procedure. In someembodiments, the spinal stabilization anchor can be inserted into acancellous region of the bone.

In some embodiments, the spinal stabilization anchor 2 may be inserteddirectly through the hole 37. In other embodiments, as illustrated inFIGS. 3A-B, the spinal stabilization anchor 2 can be inserted through acannula or sleeve 34 to the bone. Optionally, the sleeve 34 may includeone or more alignment members 36. As illustrated in FIG. 3A, thealignment member 36 can be a groove that is configured to accept theprotrusion 16 on the collar 6 of the spinal stabilization anchor 2. Insome embodiments, the step of inserting the spinal stabilization anchor2 into the bone can further include securing the spinal stabilizationanchor 2 into the bone using a linear force. For example, the spinalstabilization anchor 2 may be hammered into the bone.

Once the spinal stabilization anchor 2 is secure, the fastener member 22may be inserted into the bone. As illustrated in FIG. 3C, the fastenermember 22 may be inserted into the same hole through which the spinalstabilization anchor 2 was passed. In some embodiments, the fastenermember 22 may pass directly through the hole. In other embodiments, thefastener member 22 may be inserted through a cannula or sleeve.

After the spinal stabilization anchor 2 and the fastener member 22 havebeen inserted, they may be coupled to each other, as illustrated in FIG.3D-E. As illustrated in FIG. 2C, the coupling step may include insertingthe head 4 of the spinal stabilization anchor 2 into the recess 28 ofthe distal tip 26 of the fastener member 22. In use, the fastener member22 may be coupled, hitched, or connected to the spinal stabilizationanchor 2 by applying a linear force, e.g., by pushing, the distal tip 26onto the head 4. This pressure may cause the head 4 to compress andenter the recess 28 of the distal tip 26, where the head 4 may expand.The lip 30 may advantageously prevent the head 4 from backing out of therecess 28. While the head 4 of the spinal stabilization anchor 2 isdisposed within the recess 28 of the fastener member 22, the fastenermember 22 may advantageously be pivotable about the spinal stabilizationanchor 2. In some embodiments, the head 4 of the spinal stabilizationanchor 2 and the recess 28 of the fastener member 22 may function like aball and socket joint.

As described herein, fastener members, such as pedicle screws and otherbone screws, may occasionally move back and forth within a bone,eventually enlarging the hole and causing the fastener members to loosenor back out from the vertebra within which they were implanted. Amongother reasons, this phenomenon, sometimes referred to as the “windshieldwiper effect.” may be the result of being implanted in bone that isparticularly porous, weak, and/or lacking sufficient density. When thefastener members come loose, the structural integrity of the overallconstruct may be affected. In some instances, revision surgery is usedto correct this loosening, for example, but replacing the original screwwith a larger screw.

Advantageously, the spinal stabilization anchor 2 described herein canreduce the likelihood that a fastener member will loosen or back outfrom a vertebral body by increasing the stability of the interfacebetween the fastener member and the vertebral body. Those skilled in theart may appreciate that the interface between the coupled spinalstabilization anchor 2 and the fastener member 22, as illustrated inFIG. 2C, can allow the fastener member 22 to pivot relative to thespinal stabilization anchor 2. If the fastener member 22 moves back andforth within a bone, it may pivot relative to the spinal stabilizationanchor 2 without backing out from the bone.

Additionally, the spinal stabilization anchor 2 and fastener member 22described herein may be used advantageously in a revision procedure. Asdescribed herein, one method of performing a revision procedure mayinclude removing the existing fastener member and inserting a newfastener member having a larger diameter to be secured within theenlarged hole created by the windshield wiper effect. However, a largerdiameter fastener member may not be required when using the devicesdescribed herein, since the fastener member 22 can be secured to a boneby virtue of being coupled to the spinal stabilization anchor 2, ratherthan relying solely on being secured within the enlarged hole.

Turning now to FIGS. 4A-D, a perspective view of various components of aspinal stabilization system 200 is illustrated in accordance withembodiments described herein. As illustrated in FIGS. 4A-D, the spinalstabilization system 200 can include a fastener member 202, an elevationmember 204, and a coupling member 206. In some embodiments, the spinalstabilization system 200 can further include a locking member 208, asillustrated in FIG. 6F.

As illustrated in FIG. 4A, the fastener member 202 can include athreaded shank 210 and a head 212. The threaded shank 210 may extendlongitudinally from the head 212. In some embodiments, the fastenermember 202 can be monolithic. In some embodiments, the head 212 can bethreaded (e.g., can include exterior and/or interior threading).Additionally, in some embodiments, the head 212 can include a socket214. In some embodiments, the head 212 can include a cylindrical (e.g.,constant diameter) outer surface. For example, in some embodiments thehead 212 may be referred to as a post. In some embodiments where thehead 212 includes exterior threading, the threaded head can include aconstant major thread diameter and/or a constant minor thread diameter.In embodiments where the head 212 is cylindrical and includes exteriorthreading, it may be referred to as a threaded post. In someembodiments, the fastener member 202 may be referred to as a postedscrew. In some embodiments, the fastener member 202 may be a pediclescrew, such as a monoaxial or polyaxial pedicle screw. The socket 214can be configured to receive a driver, such as a screwdriver or a hexkey. As described further herein, the socket 214 can also be configuredto receive a portion of the coupling member 206. The lateralcross-sectional shape of the socket 214 can vary to accommodate variousdrivers, and can be, for example, a slot, cross, star, triangle, square,hexagon, or pentagon. In some embodiments, at least a section of thesocket 214 can have a hexagonal lateral cross-section, as illustrated inFIG. 4A.

As illustrated in FIG. 4B, the elevation member 204 can be configured tobe disposed on the fastener member 202. As illustrated, for example, inFIGS. 5A-C, the elevation member 204 can include a body 218. The body218 can include a proximal face 224, a distal face 226, and a threadedhole 220 extending therethrough from the proximal face 224 to the distalface 226, as illustrated in FIGS. 4B-C. Advantageously, the threadedhole 220 can be configured to mate with the threaded head 212. Theelevation member 204 can further include a first connector member 222,as illustrated in FIGS. 5A-B. The first connector member 222 can beconfigured to receive and/or couple to at least a portion of thecoupling member 206, as described further herein. In some embodiments,the first connector member 222 can be a receptacle on the proximal face224 of the elevation member 204. For example, in one embodiment, thefirst connector member 222 may be an indentation, recess, channel, orgroove on the proximal face 224 of the elevation member 204. In anotherexample, the first connector member 222 can be a circular channelsurrounding the threaded hole 220, as illustrated in FIGS. 5A-C. Inother embodiments, the first connector member 222 can include aplurality of grooves surrounding the threaded hole 220. In yet otherembodiments, the first connector member 222 can include a protrusion,phalange, or lip. In these embodiments, the first connector member 222can couple to at least a portion of the coupling member 206 by beingreceived in at least a portion of the coupling member 206.

The elevation member 204 can include an outer surface 228, asillustrated in FIGS. 5A-C. The outer surface 228 can be configured tocouple with a tool, such as a driver, wrench, or other implement thatcan apply torque to the elevation member 204. As depicted in FIGS. 4B-C,in some embodiments the elevation member 204 can be a gear member. Inthese embodiments, the outer surface 228 of the elevation member 204 caninclude a plurality of protrusions, such as teeth 230. Those skilled inthe art may appreciate that the teeth 230 may be configured to mesh withthe teeth of another gear member that may be mounted on a driver, forexample. The gear teeth may have any configuration as known in the art.For example, the elevation member 204 can be a spur gear, a straight-cutgear, a helical gear, or a bevel gear. In some embodiments, the teeth230 may be aligned parallel to a longitudinal axis 216.

Advantageously, the elevation member 204 can also be configured toadjust a length 266 of the spinal stabilization system 200 (e.g., from aproximal end 234 of the coupling member 206 to a distal tip 235 of thefastener member 202). In some embodiments, the elevation member 204 canbe configured to rotate about the axis 216 of the spinal stabilizationsystem 200. In other embodiments, the fastener member 202 and/or thelocking member 208 may also be configured to rotate about the axis 216.

The coupling member 206 may be configured to couple the fastener member202 to a rod. As illustrated, for example, in FIG. 4C, the couplingmember 206 can include an upper portion 236 and a lower portion 238. Theupper portion 236 may be configured to receive a rod. For example, theupper portion 236 of the coupling member 206 may include two arms 240,242 defining a rod-receiving channel 232, as illustrated in FIGS. 5A-C.The upper portion 236 can also include a seat 244 configured to contactthe rod. Upon insertion and reduction, the rod may rest upon the seat244. The shape of the seat 244 can be configured to accommodate theshape of the rod, and can be, for example, rounded, U-shaped, orpartially cylindrical. The upper portion 236 of the coupling member 206may also include a proximal end 234 configured to engage the lockingmember 208. For example, in some embodiments, the proximal end 234 caninclude interior threading. In other embodiments, the proximal end 234can include, for example, a groove and/or a cam surface. The upperportion 236 can optionally also include one or more tool-receivingrecesses 246, 248, as illustrated in FIGS. 5A-C.

At least a section of the lower portion 238 of the coupling member 206may be configured to engage the fastener member 202. As illustrated inFIGS. 5A-C, the lower portion 238 can include a stem 250. The stem 250can be configured to be received, and/or keyed (e.g., wedged orfastened) in the socket 214 of the fastener member 202. In theseembodiments, the shape of the stem 250 and socket 214 can prevent thecoupling member 206 and fastener member 202 from rotating relative toone another. The stem 250 can take on a variety of shapes, such as arectangle, cross, star, triangle, square, hexagon, or pentagon, to fitinto and couple with the socket 214. In some embodiments, at least asection of the stem 250 can have a hexagonal lateral cross-section, asillustrated in FIG. 5C. In other embodiments, the stem 250 and thesocket 214 can both include at least a section having a hexagonallateral cross section.

At least a section of the lower portion 238 of the coupling member 206may be configured to engage the elevation member 204. In someembodiments, the lower portion 238 can include a second connector member252, as illustrated in FIGS. 5A-C. The second connector member 252 canbe configured to mate with the first connector member 222 of theelevation member 204. For example, in embodiments where the firstconnector member 222 includes a receptacle, the second connector member252 can include a protrusion which is configured to be received in thereceptacle. In one embodiment, the first connector member 222 caninclude a channel and the second connector member 252 can include a lip254.

In some embodiments, the second connector member 252 can be bendable orflexible to fit into the first connector member 252. The secondconnector member 252 can be configured to bend or flex according to avariety of means, such as by including one or more longitudinal slots256. Similarly, in these embodiments, the second connector member 252may comprise a plurality of segments 258 separated by the slots 256. Inthese embodiments, illustrated in FIGS. 5A-C, the second connectormember 252 may be referred to as a slotted collar.

As described herein, a portion of the coupling member 206 (e.g., thesecond connector member 252) may be received in a portion of theelevation member 204 (e.g., the first connector member 222). In theseembodiments, the coupling member 206 can include a protrusion and theelevation member 204 can include a receptacle. However, those skilled inthe art may appreciate that in other embodiments, a portion of theelevation member 204 (e.g., the first connector member 222) may bereceived in a portion of coupling member 206 (e.g., the second connectormember 252). In these embodiments, the elevation member 204 may includea protrusion and the coupling member 206 may include a receptacle.Accordingly, any of the protrusions and receptacles described herein maybe applied to either the elevation member 204 or the coupling member206.

As illustrated in FIG. 6F, the spinal stabilization system 200 can alsoinclude a locking member 208. The locking member 208 can be configuredto engage the upper portion 236 of the coupling member 206. In someembodiments, the locking member 208 may be configured to mate with theproximal end 234 of the upper portion 236 of the coupling member 206. Inembodiments where the proximal end 234 includes internal threading, thelocking member 208 can include external threading. For example, in theseembodiments, the locking member 208 can include a set screw. In otherembodiments, the locking member 208 can include a cam lock.

Embodiments herein are also directed to methods of installing the spinalstabilization system 200. The method may include providing the spinalstabilization system 200, which may or may not be at least partiallyassembled prior to installation. In some embodiments, the spinalstabilization system 200 may be assembled in situ (e.g., at the locationwhere the system will be installed, such as a vertebral area of apatient) as a part of the installation process. In these embodiments,the fastener member 202 may first be installed. The fastener member 202may be installed, for example, in any appropriate bone, such as avertebra, and at any appropriate location thereon, as determined bythose skilled in the art. In embodiments where the fastener member 202is a pedicle screw, the fastener member 202 may be installed in (e.g.,screwed or threaded into) the pedicle of a vertebra. The fastener member202 may be installed using methods known to those skilled in the art.For example, in some embodiments, a passageway may be drilled and thefastener member 202 may be installed through a sheath, tube, or sleeve,and/or over a guide wire.

After the fastener member 202 is installed, the elevation member 204 maybe coupled with the fastener member 202. In embodiments where theelevation member 204 includes a through bore with internal threading andthe fastener member 202 includes a threaded head 212, the elevationmember 204 may be coupled with the fastener member 202 by threading theelevation member 204 onto the threaded head 212.

The coupling member 206 may then be coupled with the fastener member 202and the elevation member 204. In embodiments where the coupling member206 includes a stem 250 and the head 212 of the fastener member 202includes socket 214, the step of coupling the coupling member 206 withthe fastener member 202 may include inserting the stem 250 into thesocket 214, as illustrated in FIGS. 5A-C. The step of coupling thecoupling member 206 with the elevation member 204 may include mating thefirst and second connector members 222, 252. In embodiments where secondconnector member 252 of the coupling member 206 includes a protrusionand the first connector member 222 of the elevation member 204 includesa receptacle, this step may include applying a distal (e.g., downward)force by pushing, sliding, snapping, and/or clicking the coupling member206 onto the elevation member 204 so that the protrusion of the secondconnector member 252 is received within the receptacle of the firstconnector member 222. In one example where the first connector member222 of the elevation member 204 includes a channel and the secondconnector member 252 of the coupling member 206 includes a slottedcollar with a lip 254, this step may include inserting the lip 254 intothe channel, for example, by pushing or snapping the slotted collar intothe channel.

In some embodiments, the spinal stabilization system 200 may be at leastpartially assembled prior to installation. For example, the fastenermember 202 and the elevation member 204 may be coupled as illustrated inFIG. 4B and installed, and then the coupling member 206 may be coupledwith the construct in situ. In another example, the fastener member 202,elevation member 204, and coupling member 206 may be assembled asillustrated in FIG. 4D and as described herein prior to being installed.One example of a fastener member 202, elevation member 204, and couplingmember 206 installed in a vertebra is illustrated in FIG. 6A.

Once the fastener member 202, elevation member 204, and coupling member206 are assembled and/or installed, a rod 262 may be inserted into therod-receiving channel 232, as illustrated in FIG. 6B. Any rods known inthe art may be used with the spinal stabilization system 200 describedherein. Additional tools, such as a rod reducer 260, may also be used toinsert the rod 262 into the rod-receiving channel 232, as illustrated inFIG. 6B. The rod 262 may be secured against the seat 244 in therod-receiving channel 232 by engaging the locking member 208 with theproximal end 234 of the coupling member 206. In some embodiments, thelocking member 208 may be delivered to the spinal stabilization system200 through a cannula in the rod reducer 260. In embodiments where thelocking member 208 includes a set screw and the proximal end 234 of thecoupling member 206 includes an internally-threaded section, this stepcan include threading the set screw into the internally-threadedsection. When the rod is secured in the rod-receiving channel, it maycontact both the seat 244 and a distal surface of the locking member208.

After the rod is secured in the rod-receiving channel, the position ofthe coupling member 206 may advantageously be adjusted along alongitudinal axis 264 of the spinal stabilization system 200, asillustrated in FIG. 6C. This may be accomplished by rotating theelevation member 204. As illustrated in FIGS. 6D-E, the elevation member204 may be rotated by a driver 266. In embodiments where the elevationmember 204 includes a gear member, the driver 266 can include a secondgear 268 that is configured to mesh with the gear teeth of the elevationmember 204. As further illustrated in FIGS. 6D-E, the driver 266 may beconfigured to couple with the rod reducer 260.

In use, because the elevation member 204 can be coupled to the couplingmember 206, as the elevation member 204 is threaded in the proximal(e.g., upwards) direction, the coupling member 206 may also be pushedupwards, as illustrated in FIGS. 6D-E. Similarly, when the elevationmember 204 is threaded in the distal (e.g., downwards) direction, thecoupling member may also be pulled downwards. Accordingly, the length266 of the construct (e.g., from the proximal end 234 of the couplingmember 206 to the distal tip 235 of the fastener member 202) can bevaried or adjusted by rotating the elevation member 204. Advantageously,the ability to provide further adjustment to the length of the constructafter being secured to a rod can be useful in procedures where long rodsare used in conjunction with large numbers of fastener members (e.g., indeformity procedures). In these procedures, it may be difficult toprecisely align all of the rod-receiving channels prior to insertion ofthe rod. The present spinal stabilization system 200 may alleviate thisissue by enabling fine-tuning of the longitudinal position of thecoupling member 206 after the rod has been inserted and secured.

As described herein, the elevation member 204 and the coupling member206 may engage with a monoaxial fastener member (e.g., a fastener membercapable of engaging the coupling member 206 at a single angle). However,those skilled in the art may appreciate that in other embodiments, theelevation member 204 and the coupling member 206 may engage with apolyaxial fastener member (e.g., a fastener member capable of engagingthe coupling member 206 at multiple angles). For example, the couplingmember 206 may be modified using techniques known in the art toaccommodate the polyaxial fastener members described herein, such asthose used with spinal stabilization system 400. Additionally, someembodiments of the spinal stabilization system 200 may include or becombined with features of other spinal stabilization systems describedherein.

Turning now to FIG. 7A-12, a spinal stabilization system 400 and itscomponents are illustrated in accordance with embodiments describedherein. The spinal stabilization system 400 can include a fastenerassembly 402 and a clamp assembly 404, as illustrated in FIG. 7B.

The fastener assembly 402 can include a fastener member 406 and acompression member 408, as illustrated in FIG. 8. The fastener member406 can include a threaded shank 410. The threaded shank 410 can extendlongitudinally from a head 412. In some embodiments, the fastener member406 can be monolithic. In some embodiments, the head 412 can be threaded(e.g., can include exterior and/or interior threading). The head 412 caninclude a cylindrical (e.g., constant diameter) outer surface. Forexample, in some embodiments, where the head 412 is cylindrical, it maybe referred to as a post. In other embodiments where the head 412 iscylindrical and includes exterior threading, it may be referred to as athreaded post. In these embodiments, the threaded head 412 can include aconstant major thread diameter and/or a constant minor thread diameter.In some embodiments, the fastener member 406 may be referred to as aposted screw. In some embodiments, the fastener member 406 may be apedicle screw, such as a monoaxial or polyaxial screw. In someembodiments, the fastener member 406 may be a pedicle screw, such as amonoaxial or polyaxial pedicle screw. The head 412 can further include asocket 414. The socket 414 can be configured to receive a driver, suchas a screwdriver or a hex key. The lateral cross-sectional shape of thesocket 414 can vary to accommodate various drivers, and can be, forexample, a slot, cross, star, triangle, square, hexagon, or pentagon. Insome embodiments, at least a section of socket 414 can include ahexagonal lateral cross-section.

As illustrated in FIG. 8, the compression member 408 can include a head416 and an elongate body 418. The head 416 can have a rounded outersurface (e.g., can include a spherical or spheroidal segment). The head416 can have a lateral diameter that is greater than a lateral diameterof the elongate body 418. In some embodiments, the elongate body 418 canhave a constant-diameter outer surface. In other embodiments, theelongate body 418 can include a distal portion 424, having a taperedouter surface.

The compression member 408 can also include a longitudinal bore 420extending therethrough. A portion of the longitudinal bore (e.g., aproximal portion within the head 416) can include a socket 422. Thesocket 422 can be configured to receive a driver, such as a screwdriveror a hex key. The lateral cross-sectional shape of the socket 422 canvary to accommodate various drivers, and can be, for example, a slot,cross, star, triangle, square, hexagon, or pentagon. In someembodiments, at least a section of socket 422 can include a hexagonallateral cross-section.

The socket 422 of the compression member 408 and the socket 414 of thefastener member 406 may each have a lateral (e.g., transverse) width ordiameter. In some embodiments, the width of the socket 422 of thecompression member 408 can be greater than the width of the socket 414of the fastener member 406. Advantageously, in some embodiments, bothsockets 414, 422 may be accessible by a driver even when the compressionmember 408 and fastener member 406 are engaged with each other, asdescribed further herein.

A portion of the longitudinal bore 420 (e.g., a distal portion withinthe elongate body 418 and/or distal portion 424) can be configured toengage the head 412 of the fastener member 406. In some embodiments, theportion of the longitudinal bore 420 that is configured to engage thehead 412 of the fastener member 406 can be configured to rotatablyengage the head 412, for example, by including internal threading thatis configured to mate with external threading on the head 412. In otherembodiments, the compression member 408 can be configured to slideablyengage the head 412 of the fastener member 406 (e.g., by including acombination of a cam member and a groove on the head 412 and thecompression member 408). In embodiments where the compression member 408is coupled to, engaged with, and/or threaded onto the fastener member406, the fastener assembly 402 may be referred to as being assembled.

As illustrated in FIGS. 9A-B, the clamp assembly 404 can include a clampmember 426, a coupling member 428, a first locking member 430, and asecond locking member 432. The clamp member 426 may include an innersurface 434 and an outer surface 436. The inner surface 434 may beconfigured to receive the head 416 of the compression member 408thereon. In some embodiments where the head 416 is curved or rounded,the inner surface 434 may also be curved or rounded, optionally to matcha degree of curvature of the head 416. The outer surface 436 may beconfigured to engage the coupling member 428. The outer surface 436 mayalso be curved or rounded, optionally to match a degree curvature of asurface of the coupling member 428. In some embodiments, the outersurface 436 can include an engagement feature (e.g., a groove orprojection) that can mate with a corresponding feature on the couplingmember 428.

The clamp member 426 may also include a chamber 442 that extends from aproximal opening 440 to a distal opening 438. The proximal opening 440may be sized and/or configured to receive the fastener assembly 402therethrough. In some embodiments, the proximal opening 440 may have adiameter that is greater than or equal to the diameter of the head 416.The distal opening 438 may be configured to receive the fastener member406 and/or elongate body 418 of the compression member 408 therethrough.The distal opening 438 may have a diameter that is greater than adiameter of the elongate body 418 and less than a diameter of the head416. Accordingly, the head 416 may rest within the chamber 442 and/or onthe inner surface 434 of the clamp member 426 without passing throughthe distal opening 438.

The clamp member 426 may be expandable and/or contractible. In someembodiments, the diameter of the clamp member 426 may reversiblyincrease or decrease upon the application or release of an externalforce. Consequently, the volume of the chamber 442 may also beconfigured to increase or decrease. In some embodiments, the clampmember 426 may be configured to contract (e.g., compress, clamp, orconstrict) around the head 416 of the compression member 408. In someembodiments, the clamp member 426 can include a slot 444, as illustratedin FIG. 7A. In some embodiments, the slot 444 can extend partially fromthe proximal opening 440 to the distal opening 438, or vice versa. Inother embodiments, the slot 444 can extend completely from the proximalopening 440 to the distal opening 438. In other embodiments, the clampmember 426 can include a plurality (e.g., two, three, four, or more) ofslots. The shape of the slot 444 may vary. In some embodiments, the slot444 may be a straight line. In other embodiments, the slot 444 mayinclude a plurality of straight lines intersecting at one or more angles(e.g., a zigzag shape). In yet other embodiments, the slot 444 mayinclude a curved line.

In other embodiments, the clamp member 426 can include a plurality ofseparate clamp elements or pieces. In some embodiments the clamp member426 can be made of two clamp elements. In other embodiments, the clampmember 426 can include two, three, four, or more clamp elements. Eachclamp element can include a curved or rounded inner and outer surface,as discussed herein with respect to the singular clamp member 426. Theclamp elements may be equally sized and shaped.

In some embodiments, the inner surface 434 of the clamp member 426 caninclude a roughened surface. As illustrated in FIG. 9A, in someembodiments, the inner surface 434 can include threading. In otherembodiments, the roughened surface can include one or more features suchas threads, grooves, bumps, ridges, knurling, and knobs.

As illustrated in FIGS. 9A-B, the coupling member 428 can include arod-receiving portion 446, a fastener-receiving portion 448, and alocking portion 450. The rod-receiving portion 446 can include a channel452. The channel 452 may include a longitudinal axis 458 and can beconfigured to receive a rod. The fastener-receiving portion 448 caninclude an aperture 454 having a longitudinal axis 460. As illustratedin FIG. 9A, the channel 452 may be at least partially laterally offsetfrom the aperture 454. Additionally, as illustrated in FIG. 9A, thelongitudinal axes 458, 460 may not intersect. In some embodiments, thelongitudinal axes 458, 460 may be orthogonal or transverse to eachother.

As illustrated in FIG. 9A, the locking portion can include a firstlocking receptacle 456. The first locking receptacle 456 may be at leastpartially laterally offset from the aperture 454. In some embodiments,the first locking receptacle 456 can include a threaded interiorsurface. The first locking receptacle 456 can be configured to receivethe first locking member 430. In use, the first locking member 430 maybe configured to lock or secure the fastener assembly 402 at aparticular angle relative to the clamp assembly 404. Thus, in someembodiments, the first locking member 430 may be referred to as afastener-locking member. The first locking member 430 can includeinterior and/or exterior threading. As illustrated in FIG. 9A, the firstlocking member 430 may be a screw, such as a set screw. In someembodiments, the first locking member 430 can be configured to engage asecuring member 464, such as a nut. The securing member 464 may have anenlarged head 466. The securing member 464 may also include exteriorthreading configured to engage the interior threading of the firstlocking member 430, and may be threaded into the first locking member430. In some embodiments, the interior and exterior threading on thefirst locking member 430 may be oriented in opposite directions. Thus,in use, the securing member 464 can prevent or reduce the likelihood ofthe first locking member 430 from unthreading or backing out of thefirst locking receptacle 456.

As illustrated in FIGS. 9A-B, the coupling member 428 can include atransverse slot 462. The transverse slot 462 can extend at leastpartially through the fastener-receiving portion 448 (e.g., at leastpartially across the first locking receptacle 456). The transverse slot462 can also extend at least partially through the locking portion 450(e.g., at least partially across the aperture 454). In some embodiments,the transverse slot 462 may render the aperture 454 the first lockingreceptacle 456 in fluid communication with each other (e.g., theaperture 454 and the first locking receptacle 456 may be connected,either directly or indirectly via a conduit or passageway).

As illustrated in FIG. 9A, the rod-receiving portion 446 can include asecond locking receptacle 468. The second locking receptacle 468 caninclude a longitudinal axis 470. The longitudinal axis 470 of the secondlocking receptacle 468 can be orthogonal to the longitudinal axis 458 ofthe channel 452. In some embodiments, the longitudinal axis 470 of thesecond locking receptacle 468 can intersect the longitudinal axis of thechannel 452. In some embodiments, the second locking receptacle 468 andthe channel 452 may be in fluid communication.

The second locking receptacle 468 may be configured to receive and/orengage the second locking member 432 therein. In use, the second lockingmember 432 may be configured to lock or secure a rod within the channel452. Thus, in some embodiments, the second locking member 432 may bereferred to as a rod-locking member. In some embodiments, the secondlocking receptacle 468 can include interior threading. In theseembodiments, the second locking member 432 can include exteriorthreading, and can be, for example, a set screw. As illustrated in FIG.9A, the second locking member 432 can include a distal tip 472configured to engage a rod, for example, in a friction or interferencefit. The shape of the distal tip 472 can vary. In some embodiments, thedistal tip 472 can be conical. In other embodiments, the distal tip 472can be pointed.

Those skilled in the art may appreciate that other variations on theclamp assembly may be used in combination with the fastener assembly 402as described herein. For example, in other embodiments, the couplingmember 428 may be configured such that the rod-receiving channel is notlaterally offset from the fastener assembly-receiving aperture, such aswith tulip-style coupling or housing members. In these embodiments, therod and the fastener assembly may be locked or secured at the same timeusing a single locking member.

Additionally, some embodiments of the spinal stabilization system 400may include features of other spinal stabilization systems describedherein. As one example, in some embodiments, the fastener assembly 402can include an elevation member, such as elevation member 204 or othergear member, that can be disposed on or adjacent to the compressionmember 408. In these embodiments, the overall length of the assembly maybe adjusted by rotating the elevation member, as described herein withrespect to the spinal stabilization assembly 200. The elevation member204 may thus be configured to translate the compression member 408 alonga longitudinal axis. Furthermore, the coupling element 206 may bemodified using techniques known in the art to accommodate a polyaxialfastener, such as the polyaxial fastener assembly 402. For example, thecoupling element 206 may be modified to include a bore extendingtherethrough, the bore having a rounded interior surface that isconfigured to receive the head 416 of the compression member 408thereon.

Embodiments herein are also directed to methods of installing the spinalstabilization system 400. In some embodiments, methods can includeproviding an assembled spinal stabilization system 400. One example ofan assembled spinal stabilization system 400 is illustrated in FIG. 7A.In these embodiments, the fastener assembly 402 may be assembled bycoupling the compression member 408 and fastener member 406, asdescribed herein. The clamp member 426 may be inserted into or disposedwithin the aperture 454 of the coupling member 428. As described herein,in some embodiments the clamp member 426 can include a projection thatis configured to be received in a groove within the aperture 454. Inthese embodiments, the clamp member 426 may be snapped or clicked intoengagement with the aperture 454 of the coupling member 428. The head416 of the assembled fastener assembly 402 may be disposed within thechamber 442 of the clamp member 426, with the elongate body 418 disposedin the distal opening 438. In some embodiments, this configuration maybe achieved by inserting the assembled fastener assembly 402, with thefastener member 406 as the leading end, into the chamber 442 from theproximal opening 440 towards the distal opening 438 of the clamp member426 (e.g., may be top-loading). In other embodiments, this configurationcan be achieved by inserting the assembled fastener assembly 402, withthe compression member 408 as the leading end, into the chamber 442 fromthe distal opening 438 towards the proximal opening of the clamp member426 (e.g., may be bottom-loading).

In some embodiments, the first locking member 430 may be threaded intothe first locking receptacle 456, and the securing member 464 may bethreaded into the first locking member 430. The first locking member 430and the securing member 464 may be loosely threaded to allow the head416 to pivot within the clamp member 426. In some embodiments, thesecond locking member 432 may be threaded into the second lockingreceptacle 468. The second locking member 432 may also be looselythreaded so as to minimize interference with the insertion of a rod intothe channel 452. Those skilled in the art may appreciate that in otherembodiments, the first locking member 430, securing member 464, and/orsecond locking member 432 may not form a part of the spinalstabilization system 400 as assembled prior to installation. Rather,they may be added to the system when the head 416 is secured within theclamp member 426 and/or when the rod is secured within the channel 452,as described further herein.

Once the spinal stabilization system 400 is assembled, or an assembledsystem is provided, the fastener member 406 may be inserted into a bone.As illustrated in FIG. 10A, the fastener member 406 may be inserted intoa pedicle; however, in other embodiments the fastener member 406 may beinserted into another part of a vertebra or in a different bone. Thefastener member 406 may be inserted into a bone according to methodsknown to those skilled in the art. In one example, prior to installingthe fastener member 406, the installation site may be prepared bycreating (e.g., drilling) a hole through which the fastener member 406may pass. For example, a hole may be drilled, and the fastener member406 may be driven or threaded into the hole. As illustrated in FIG. 10B,the socket 414 of the fastener member 406 may receive a driver 474,which can transfer torque to the fastener member 406. Advantageously,because the socket 422 of the compression member 408 may be larger(e.g., may have a greater diameter) than the socket 414 of the fastenermember 406, the fastener member 406 can be accessed by a driver evenafter the fastener assembly 402 is assembled. Additionally, this featurecan allow the fastener member 406 and the compression member 408 to beactuated separately.

A rod 476 may then be inserted into the channel 452, as illustrated inFIGS. 11A-B. Any rods known in the art may be used with the spinalstabilization system 400, such as straight, curved, hard, soft,deformable, and/or expandable rods. Furthermore, the rod may be insertedusing methods and/or devices known to those skilled in the art. Forexample, a rod reducer, fork, and/or persuader may be used to insert therod 476 into the channel 452. Additionally, as illustrated in FIG. 11C,multiple spinal stabilization systems 400 may be installed, for example,in a spine. In these embodiments, the step of inserting the rod caninclude inserting the rod 476 into the channel 452 of each spinalstabilization system 400.

Advantageously, the position (e.g., length and/or angle) of the fastenerassembly 402 may be adjusted after the rod 476 has been inserted in thechannel 452. The length may be adjusted by adjusting a position of thecompression member 408 along a longitudinal axis 478, as illustrated inFIG. 12. The driver 474 can engage the socket 422 to translate thecompression member 408 up and down along the head 412 of the fastenermember 406, thereby modifying the overall length (e.g., height) of thefastener assembly 402. Advantageously, driver 474 can include an innerdrive shaft 475 and an outer drive shaft 477, as illustrated in FIGS.10B and 12. Accordingly, driver 474 can be used to drive the fastenermember 406 into a bone as well as to adjust the length of the fastenerassembly 402. However, those skilled in the art may appreciate thatother drivers may also be used.

Because the compression member 408 may be engaged with the clampassembly 404, translation or adjustment of the compression member 408can also additionally result in translation or adjustment of the clampassembly 404. Advantageously, the position of the spinal stabilizationsystem 400 can be adjusted without having to remove and/or reshape therod 476. In procedures utilizing a large number of spinal stabilizationsystems and/or a long rod, such as deformity procedures, this capabilitycan potentially save time and reduce risk to a patient.

As described herein, the fastener assembly 402 may be configured toengage the clamp assembly 404 at multiple angles. The angle of thefastener assembly 402 relative to the clamp assembly 404 may be adjustedby pivoting the head 416 of the fastener assembly 402 within the chamber442 of the clamp member 426, and/or by pivoting the clamp member 426(and, consequently, the coupling member 428) about the head 416 of thefastener assembly 402. The angle of the fastener assembly 402 relativeto the clamp assembly 404 may then be secured by compressing the clampmember 426 around the head 416. This may be accomplished, for example,by threading the first locking member 430 into the first lockingreceptacle 456 and onto the securing member 464. As the first lockingmember 430 and the securing member 464 are brought closer together, theslot 462 may be squeezed or compressed. In turn, the aperture 454 mayalso be compressed, thereby also compressing the clamp member 426.

After the rod 476 has been inserted into the channel 452, the secondlocking member 432 may be inserted (e.g., threaded) into the secondlocking receptacle 468 to secure the rod in the channel 452. Thoseskilled in the art may appreciate that the second locking member 432 canpass through the second locking receptacle 468 to the channel 452. Whena rod is in the channel 452, the second locking member 432 can applyfriction to the rod, thereby securing it within the channel 452. Thoseskilled in the art may appreciate that the steps of adjusting the lengthof the fastener assembly 402, adjusting and securing the angle of thefastener assembly 402, and securing the rod 476 in the channel 452 mayoccur in any order. In some embodiments, the rod 476 can be locked inthe channel 452 either before or after any or all of the steps ofadjusting the length of the fastener assembly 402, adjusting the angleof the fastener assembly 402, and securing the angle of the fastenerassembly 402.

In some embodiments, all or a portion of the spinal stabilization system400 can be assembled as part of the installation process. For example,in one embodiment, all of the components can be pre-assembled except forthe second locking member 432, which can be added to the system afterthe rod 476 is placed in the channel 452. In other embodiments, thefastener assembly 402, either assembled or unassembled, may be insertedinto a bone prior to coupling with the clamp assembly 404. Aftercoupling of the fastener assembly 402 with the clamp assembly 404, theremaining steps for installing the spinal stabilization system 400 asdescribed herein may be followed.

Turning now to FIGS. 13-17, a spinal stabilization system 600 and itscomponents are illustrated in accordance with embodiments describedherein. The stabilization system 600 can include a fastener member 602,a torsion member 604, a relief member 606, and a compression member 608,as illustrated in FIGS. 13-14. As illustrated in FIG. 13, the fastenermember 602 can include a head 610, a threaded body or shank 612extending longitudinally from the head 610, and a socket 614. In someembodiments, the head 610 can include a cylindrical (e.g., constantdiameter) outer surface. For example, in some embodiments the head 610may be referred to as a post. In some embodiments, the head 610 caninclude a smooth (e.g., non-threaded) exterior surface. In someembodiments where the head 610 includes exterior threading, the threadedhead can include a constant major thread diameter and/or a constantminor thread diameter. In embodiments where the head 610 is cylindricaland includes exterior threading, it may be referred to as a threadedpost. In some embodiments, the fastener member 602 may be a screw, suchas a bone screw. In some embodiments, the fastener member 602 may bereferred to as a screw.

As illustrated in FIG. 13, the fastener member 602 can also include aproximal surface 616. The proximal surface 616 may be configured tocontact a portion of the relief screw 606, as described further herein.In some embodiments, the proximal surface 616 can be smooth. In otherembodiments, the proximal surface 616 can include an engagement feature.As illustrated in FIG. 13, the engagement feature can include aplurality of steps or ratchets that can enhance the interface betweenthe proximal surface 616 of the fastener member and the relief screw606.

As illustrated in FIG. 15A, the socket 614 can extend through the head610 and at least partially through the threaded body 612. The shape ofthe lateral (e.g., transverse) cross-section of the socket 614 can vary,and can include, for example, a circle, oval, slot, star, cross,triangle, square, hexagon, or pentagon. For example, at least a portionof the socket 614 can include a hexagonal lateral cross-section. In someembodiments, the socket 614 can have a lateral cross-sectional shapethat varies along a length of the fastener member 602. For example, thesocket 614 can have a circular transverse cross-section in the head 610and an angular transverse cross-section in the threaded body 612. In oneembodiment, the socket 614 can have a hexagonal lateral cross-section inthe threaded body 612. The diameter or width of the socket 614 can alsovary along the length of the fastener member 602. In some embodiments,the diameter or width of the socket 614 can be greater in the threadedbody 612 as compared to in the head 610, as illustrated in FIG. 15A.

As illustrated in FIG. 13, the torsion member 604 can include a distalsection 618, a body 620, and a proximal section 622. In someembodiments, the torsion member 604 may be referred to as a torsionshaft. The distal section 618 may be configured to be received ordisposed within the socket 614 of the fastener member 602. The shape ofthe lateral (e.g., transverse) cross-section of the torsion member 604may vary, and can include, for example, a circle, oval, slot, cross,star, triangle, square, hexagon, or pentagon. In some embodiments, thetorsion member 604 can have a transverse cross-sectional shape thatvaries along a length of the torsion member 604. In some embodiments,the distal section 618 can have a hexagonal lateral cross-section andthe proximal section 622 and body 620 can each have a circular lateralcross-section. Accordingly, in some embodiments the body 620 can becylindrical. The size of the lateral cross-section, diameter, or widthof the torsion member 604 can also vary along the length of the fastenermember. For example, the distal section 618 of the torsion member 604can include a cross-section, diameter, or width that is greater than across-section, diameter, or width of the body 620. In some embodiments,the distal section 618 may be configured to not be rotatable within thesocket 614. In other embodiments, the distal section 618 may also beconfigured to rotate within the socket 614.

In some embodiments, at least a portion of the torsion member 604, suchas the body 620, may be flexible (e.g., may be configured to flex, bend,twist, or contort under pressure from one or more vertebrae). The body620 may be configured to flex using a variety of different techniques.In some embodiments, the body 620 can include at least one incision,opening, notch, slit, or cut 636. In some embodiments, the body 620 caninclude a plurality of cuts. The cut 636 may include one or more linear(e.g., straight), angular, and/or curved sections. The cut 636 mayrevolve or rotate about a longitudinal axis. For example, the cut 636can be a helical cut that extends along a length of the body 620, asillustrated in FIG. 13. In embodiments including a cut, the body 620 maybe configured to flex as the result of structural instability that maybe generated by the cut 636. In other embodiments, the body 620 caninclude at least one groove or trench. In yet other embodiments, thebody 620 may include a flexible or malleable material. The proximalsection 622 can include an externally-threaded portion 624 and/or atool-receiving recess 626. The tool-receiving recess 626 can beconfigured to receive a driver, such as a screwdriver or hex key, orother insertion tool. The lateral cross-sectional shape of the recess626 can vary to accommodate various drivers, and can be, for example, aslot, cross, star, triangle, square, hexagon, or pentagon. In someembodiments, at least a section of the recess 626 can have a hexagonallateral cross-section.

The relief member 606 can include a body 628. The body 628 can bebounded by a proximal end 630 and a distal end 632, as illustrated inFIG. 14. The relief member 606 can also include a bore 634 extendinglongitudinally therethrough. The distal end 632 may be configured tocontact a portion of the fastener member 602, such as the proximalsurface 616, as described further herein. In some embodiments, thedistal end 632 can be smooth. In other embodiments, the distal end 632can include an engagement feature. As illustrated in FIG. 14, theengagement feature can include a plurality of steps or ratchets that canenhance the interface between the proximal surface 616 of the fastenermember 602 and the distal end 632 of the relief member 606. In someembodiments, the engagement feature on the distal end 632 of the reliefmember 606 can mate or mesh with the engagement feature on the proximalsurface 616 of the fastener member.

The bore 634 can include a proximal end that includes a tool-receivingrecess 638, illustrated in FIG. 15A. The tool-receiving recess 638 canbe configured to receive a driver, such as a screwdriver or hex key, orother insertion tool. The lateral cross-sectional shape of the recess638 can vary to accommodate various drivers, and can be, for example, aslot, cross, star, triangle, square, hexagon, or pentagon. In someembodiments, at least a section of the recess 638 can have a hexagonallateral cross-section. The bore 634 can include an internally-threadedportion 635 that is configured to mate with the externally-threadedportion 624 of the torsion member 604. The body 628 can also include anexternally-threaded portion, as illustrated in FIG. 14. In someembodiments, the relief member 606 can include external threading alongits length in one or more sections. In other embodiments, the body 628can include external threading along its entire length. In embodimentsincluding internal and/or external threading, the relief member 606 maybe referred to as a relief screw. The relief member 606 may becylindrical (e.g., may include a constant outer diameter). Inembodiments where the entire body 628 includes exterior threading, thethreading may include a constant major diameter and/or a constant minordiameter.

As illustrated in FIGS. 14-15B, the compression member 608 can include abody 640 and a proximal end 642. The body 640 can be elongate and/orcylindrical (e.g., can have a constant outer diameter). The proximal end642 can have an outer width or diameter that is greater than an outerwidth or diameter of the body 640. The body 640 can also have an innerand/or outer diameter that is greater than an outer diameter of therelief member 606. Additionally, the proximal end 642 can include atapered outer surface (e.g., can have an outer diameter that increasesor decreases in either the distal or proximal direction).

The compression member 608 can also include a bore 646 extendinglongitudinally therethrough. As illustrated in FIG. 15A, the bore 646can include one or more internally-threaded portions 648. In someembodiments, the entire bore can include internal threading (e.g., thebore 646 can include one internally-threaded portion 646 that spans anentire length of the bore 646). The internally-threaded portion 648 canbe configured to mate with the externally-threaded portion of the reliefmember 606. The compression member 608 may be configured to thread ontoat least a portion of the relief member 606 and may be referred to as acompression nut. The proximal end 642 can include a tool-receivingrecess 644. The tool-receiving recess 644 can be configured to receive adriver, such as a screwdriver or hex key, or other insertion tool. Thelateral cross-sectional shape of the recess 644 can vary to accommodatevarious drivers, and can be, for example, a slot, cross, star, triangle,square, hexagon, or pentagon. In some embodiments, at least a section ofthe recess 644 can have a hexagonal lateral cross-section.

Embodiments herein are also directed to methods of installing the spinalstabilization system 600. These embodiments may include providing anassembled spinal stabilization system 600. An example of an assembledsystem is illustrated in FIGS. 15A-B. When assembled, the distal section618 of the torsion member 604 may be disposed within the socket 614 ofthe fastener member 602. In some embodiments, the torsion member 604 maybe configured to be unremovable from the socket 614 of the fastenermember 602. The relief member 606 may be threaded onto theexternally-threaded portion 624 of the torsion member 604. Thecompression member 608 may be threaded onto the externally-threadedportion of the body 628 of the relief member 606. Advantageously, whileassembled, all of the tool-receiving recesses 626, 638, 644 may beaccessible by a driver, such as a hex key. Additionally, when assembled,all components, and the system 600 overall, may share (e.g., may beconfigured to rotate about) a longitudinal axis 650. Those skilled inthe art may also appreciate that the spinal stabilization system 600 mayhave a variable length, which can result from translating thecompression member 608 along the longitudinal axis 650 relative to therelief member 606. As described further herein, the spinal stabilizationsystem 600 may utilize one or more of these features so as to beconfigured to compress or shift two bones or fragments thereof together,and may be referred to as a compression system.

The method can also include creating a passageway 656 at least partiallythrough a proximal fragment or bone 652 and a distal fragment or bone654, as illustrated in FIG. 16A. The passageway 656 may pass at leastpartially through a body of the proximal bone 652 and a body of thedistal bone 654. The method may be used with any bones or fragments asappropriate. In some embodiments, the proximal and distal bones 652, 654are adjacent vertebrae, as illustrated in FIG. 16A. In theseembodiments, the methods described herein may be used to treat acondition where one or more vertebrae are displaced and/or misaligned,such as spondylolisthesis. In one embodiment, at least one of theproximal bone and the distal bone may be anteriorly displaced prior tothe installation of the system.

The passageway 656 may be created using methods known in the art, suchas drilling. In some embodiments, the passageway 656 may have a variablediameter. For example, the passageway 656 may have a first section 658with a first diameter and a second section 660 with a second diameter,wherein the first diameter is smaller than the second diameter. In someembodiments, the first diameter is smaller than the diameter of theproximal end 642 of the compression member 608. In other embodiments,the second diameter may be equal to or greater than the diameter of theproximal end 642. In some embodiments, the diameter of the passageway656 may be smaller in the distal bone 654 than in the proximal bone 652.In other embodiments, the second section 660 having an enlarged diametermay be disposed within the proximal bone 652.

After the passageway 656 is created, the body 612 of the fastener member602 may be inserted (e.g., threaded) through the passageway 656 into thedistal bone 654, as illustrated in FIG. 16B. Torque may be applied tothe fastener member 602 by engaging a driver with the tool-receivingrecess 638 on the relief member 606. Because the relief member 606 andthe fastener member 602 may be engaged via the torsion member 604, theforce applied to the relief member 606 may be transferred to thefastener member 602. In some embodiments, the spinal stabilizationsystem 600 may be inserted directly into the passageway 656. In otherembodiments, all or a portion of the spinal stabilization system 600 maybe inserted through a sheath, tub, or sleeve, and/or over a guide wire.Advantageously, the spinal stabilization system 600 may be configured tobe installed in a minimally-invasive and/or percutaneous procedure.

After the fastener member 602 is inserted into the distal bone 654, thecompression member 608 may be inserted (e.g., threaded) into theproximal bone 652, as illustrated in FIG. 16C. Torque may be applied tothe compression member 608 by engaging a driver with the tool-receivingrecess 644. As described herein, the passageway 656 may have an enlargedsection at a proximal end of the passageway 656. In use, as thecompression member 608 is inserted into the proximal bone 652, theenlarged proximal end 642 may be inserted into the enlarged section 660of the passageway 656, but may not fit within the smaller section 658 ofthe passageway 656. As the proximal end 642 abuts the smaller section658 of the passageway 656, the torque applied by a driver mayadvantageously result in reducing the overall length of the system 600,thereby pulling or compressing the relief member 606 and compressionmember 608 components towards each other. Accordingly, when the fastenermember 602 is secured within the distal bone 654, the action of drivingthe compression member 608 through the passageway 656 may result inpulling the proximal and distal bones 652, 654 towards each other toalter the relative alignment between the two bones. As described herein,this method may advantageously be used to treat conditions where one ormore bones have been displaced, such as spondylolisthesis.

In some embodiments, the methods described herein can further includeexposing at least a portion of the torsion member 604, such as the body620, as illustrated in FIG. 16D. This step can include at leastpartially disengaging (e.g., unthreading) the relief member 606 from thetorsion member 604. This may be accomplished by coupling a driver withthe tool-receiving recess 638 and applying torque to the relief member606. Advantageously, when the body 620 is exposed, it may allow thespinal stabilization system 600 to bend, flex, and/or twist, therebyrelieving pressure on adjacent structures (e.g., facet joints). In someembodiments, the torsion member 604 may also be rotated, twisted, oruntwisted, for example, by applying torque at the tool-receiving recess626. Advantageously, this step may reduce the axial load on the torsionmember 604.

In other embodiments, the spinal stabilization system 600 may be atleast partially assembled during the installation process (e.g., may notbe fully assembled when the installation process begins). As oneexample, the torsion member 604 and the fastener member 602 may beassembled as illustrated in FIG. 13 and inserted into a bone.Thereafter, the relief member 606 may be threaded onto the torsionmember 604, and the compression member 608 may subsequently be threadedonto the relief member 606. In another embodiment, the fastener member602, torsion member, and relief member 606 may be assembled prior toinstallation, and the compression member 608 may be threaded on to therelief member 606 in situ. Those skilled in the art may appreciate thatother variations on the order of assembly and implantation may also beused. Advantageously, these variations may be appliedminimally-invasively.

In some embodiments, multiple spinal stabilization systems 600 may beinstalled in a spine, as illustrated in FIG. 17. The number andplacement of the spinal stabilization systems 600 may vary, for example,on the extent and/or orientation of the vertebral displacement. Asdescribed herein, the spinal stabilization system 600 may advantageouslybe used to treat vertebral displacement conditions, such asspondylolisthesis, with a single device that can be installed in aminimally-invasive or percutaneous procedure.

Any of the devices described above can be part of a larger spinalstabilization system including, but not limited to, any of thefollowing: rod members, screw members (including polyaxial and uniplanarscrews), plate members, spacers and cages. In addition, the devicesdescribed above can be used in conjunction with fusion devices andprosthetic devices, such as artificial discs and artificial facet jointprostheses. Furthermore, the devices can be accompanied by natural andsynthetic biological material, such as bone graft material.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims. Althoughindividual embodiments are discussed herein, the invention covers allcombinations of all those embodiments.

What is claimed is:
 1. A spinal stabilization system comprising: a screwcomprising a post, a threaded shank extending distally from the post,and a socket; a torsion shaft comprising: a distal section configured tobe received within the socket; a body comprising at least one cut; and aproximal section comprising an externally-threaded portion and atool-receiving recess; a relief screw comprising a body having anexternally-threaded portion, a proximal end having a tool-receivingrecess, and a bore extending longitudinally therethrough, wherein thebore comprises an internally-threaded section configured to mate withthe externally-threaded section of the torsion shaft; and a compressionnut comprising a proximal end having a tool-receiving recess, a body,and a bore extending longitudinally therethrough, wherein the borecomprises an internally-threaded portion configured to mate with theexternally-threaded body of the relief screw.
 2. The spinalstabilization system of claim 1, wherein at least a portion of thesocket has a hexagonal lateral cross-section.
 3. The spinalstabilization system of claim 1, wherein the post comprises acylindrical outer surface.
 4. The spinal stabilization system of claim1, wherein the distal section of the torsion shaft comprises a lateralcross-section that is larger than a lateral cross-section of the body ofthe torsion shaft.
 5. The spinal stabilization system of claim 1,wherein the distal section of the torsion shaft comprises a hexagonallateral cross-section.
 6. The spinal stabilization system of claim 1,wherein the body of the torsion shaft is cylindrical.
 7. The spinalstabilization system of claim 1, wherein the body of the torsion shaftcomprises a helical cut that extends along a length of the body.
 8. Thespinal stabilization system of claim 1, wherein the body of the torsionshaft is configured to flex under pressure from one or more vertebrae.9. The spinal stabilization system of claim 1, wherein the body of therelief screw comprises external threading along its length.
 10. Thespinal stabilization system of claim 1, wherein the proximal end of thecompression nut has an outer diameter that is greater than an outerdiameter of the body of the compression nut.
 11. The spinalstabilization system of claim 1, wherein the body of the compression nuthas a constant outer diameter.
 12. The spinal stabilization system ofclaim 1, wherein each tool-receiving recess has a hexagonalcross-section.
 13. A spinal stabilization system comprising: a fastenermember comprising a head, a threaded body extending longitudinally fromthe head, and a socket; a torsion member comprising: a distal sectionconfigured to be received within the socket, a flexible body, and aproximal section comprising an externally-threaded portion and atool-receiving recess; a relief member comprising a bore extendinglongitudinally therethrough, a body comprising external threading, and aproximal end having a tool-receiving recess, wherein the bore comprisesan internally-threaded portion configured to mate with theexternally-threaded portion of the torsion member; and a compressionmember comprising a proximal end having a tool-receiving recess and abore extending longitudinally therethrough, wherein the bore comprisesan internally-threaded portion configured to mate with the externalthreading of the relief member.
 14. The spinal stabilization system ofclaim 13, wherein the socket extends through the head of the fastenermember and into at least a portion of the threaded body.
 15. The spinalstabilization system of claim 14, wherein the socket has a circulartransverse cross section in the head and a hexagonal transverse crosssection in the threaded body.
 16. The spinal stabilization system ofclaim 13, wherein the flexible body of the torsion member comprises atleast one cut.
 17. An assembled spinal stabilization system comprising:a fastener member comprising a head, a threaded body extendinglongitudinally from the head, and a socket; a torsion member comprisinga distal section, a flexible body, and a proximal section comprising anexternally-threaded segment and a tool-receiving recess, wherein atleast the distal section is disposed within the socket of the fastenermember; a relief member comprising a body comprising external threadingand a bore extending longitudinally therethrough, wherein the borecomprises a proximal end having a tool-receiving recess and aninternally-threaded portion engaged with the externally-threaded portionof the torsion member, and a compression member comprising a boreextending longitudinally therethrough and a proximal end having atool-receiving recess, wherein the bore comprises a threaded portionengaged with the external threading of the relief member.
 18. The spinalstabilization system of claim 17, wherein the distal section of thetorsion member comprises a width that is larger than a width of the bodyof the torsion member.
 19. The spinal stabilization system of claim 17,wherein all tool-receiving recesses are accessible by a driver.
 20. Thespinal stabilization system of claim 17, wherein the system has avariable length.